Secondary battery having a structure for suppressing multi-tab short circuits

ABSTRACT

Various embodiments of the present invention relate to a secondary battery having a structure for suppressing multi-tab short circuits, and the technical problem to be solved is providing a secondary battery capable of increasing the insulation level of multi-tabs by forming insulating layers on the multi-tabs of an electrode assembly. To this end, the present invention provides a secondary battery comprising: a case; an electrode assembly accommodated inside the case and having multi-tabs; and a cap plate closing the case and having electrode terminals electrically connected to the multi-tabs of the electrode assembly, wherein the surfaces of the multi-tabs are coated with insulating layers.

TECHNICAL FIELD

Various embodiments of the present invention relate a secondary batteryhaving a structure for suppressing multi-tab short circuits.

BACKGROUND ART

A secondary battery is a power storage system that converts electricenergy into chemical energy and stores the converted energy to providehigh energy density. Unlike primary batteries that cannot be recharged,a secondary battery is rechargeable and is being widely used in ITdevices, such as a smart phone, a cellular phone, a notebook computer,or a tablet PC. In recent years, electric vehicles are drawing attentionfor protection of environmental contamination, and a trend toward theuse of high-capacity secondary batteries for electric vehicles isgrowing. The secondary battery needs to have high density, high outputand stability characteristics.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the describedtechnology and therefore it may contain information that does not formthe prior art that is already known in this country to a person ofordinary skill in the art.

TECHNICAL PROBLEMS TO BE SOLVED

Various embodiments of the present invention provide a secondary batteryhaving a structure for suppressing multi-tab short circuits. Moreparticularly, various embodiments of the present invention provide asecondary battery capable of increasing the insulation level ofmulti-tabs by forming insulating layers on the multi-tabs of anelectrode assembly.

TECHNICAL SOLUTIONS

In accordance with an aspect of the present invention, there is provideda secondary battery including a case, an electrode assembly accommodatedinside the case and having multi-tabs, and a cap plate closing the caseand having electrode terminals electrically connected to the multi-tabsof the electrode assembly, wherein the surfaces of the multi-tabs arecoated with insulating layers.

The insulating layers may include an insulating organic material.

The insulating layers may include an insulating inorganic material.

The insulating layers may include an inorganic filler and an organicbinder.

The electrode assembly may include a first electrode plate including afirst current collector plate and a first electrically active materiallayer coated on the first current collector plate, a separatorpositioned at one side of the first electrode plate, and a secondelectrode plate including a second current collector plate positioned atone side of the separator and a second electrically active materiallayer coated on the second current collector plate. The multi-tabs mayhave a structure in which the first current collector plate is upwardlyextended to an exterior side of the first electrically active materiallayer of the first electrode plate. The insulating layers and theseparator may be positioned between the multi-tabs and the secondelectrode plate. The secondary battery may further include a safetyfunction layer (SFL) located on the second electrically active materiallayer, and the insulating layers, the separator and the SFL may bepositioned between the multi-tabs and the second electrode plate. Theinsulating layers may be brought into contact with the firstelectrically active material layer. The insulating layers may be spacedapart from the first electrically active material layer. The insulatinglayers may be brought into contact with the separator.

ADVANTAGEOUS EFFECTS

As described above, various embodiments of the present invention providea secondary battery having a structure for suppressing multi-tab shortcircuits. That is to say, various embodiments of the present inventionprovide a secondary battery capable of increasing the insulation levelof multi-tabs by forming insulating layers on the multi-tabs of anelectrode assembly.

In an example embodiment, an insulating layer made of an organicmaterial, an inorganic material, and/or an organic-inorganic compositematerial, is located on one or both surfaces of a positive multi-tab ofan electrode assembly, thereby providing a triple insulating structureincluding the insulating layer between the positive multi-tab and anegative electrode plate, a separator and/or a safety function layer(SFL) (i.e., a ceramic layer coated on a surface of an negativeelectrode active material layer). Accordingly, even if the positivemulti-tab is bent in various types to be connected to an electrodeterminal, an electrical short circuit between the positive multi-tab andthe negative electrode plate can be suppressed. That is to say, theinsulation level of the positive multi-tab can be increased.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A, 1B and 1C are a perspective view, a cross-sectional view andan exploded perspective view of a secondary battery according to anembodiment of the present invention.

FIGS. 2A and 2B are a plan view and a partial cross-sectional view offirst and second electrode assemblies in a secondary battery having astructure for suppressing multi-tab short circuits according to anembodiment of the present invention.

FIGS. 3A and 3B are a plan view and a partial cross-sectional view offirst and second electrode assemblies in a secondary battery having astructure for suppressing multi-tab short circuits according to anotherembodiment of the present invention.

FIGS. 4A and 4B are a plan view and a perspective view of first andsecond electrode assemblies in a secondary battery having a structurefor suppressing multi-tab short circuits according to another embodimentof the present invention.

FIGS. 5A and 5B are enlarged cross-sectional views illustrating statesbefore and after bending multi-tabs according to an embodiment of thepresent invention.

FIGS. 6A and 6B are enlarged cross-sectional views illustrating statesbefore and after bending multi-tabs according to another embodiment ofthe present invention.

FIGS. 7A and 7B are enlarged cross-sectional views of multi-tabsaccording to another embodiment of the present invention.

FIGS. 8A to 8C are schematic views illustrating a manufacturing methodof a secondary battery having a structure for suppressing multi-tabshort circuits according to an embodiment of the present invention.

FIG. 9 is a perspective view illustrating an example of a battery moduleusing a secondary battery having a structure for suppressing multi-tabshort circuits according to an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a preferred embodiment of the present invention will bedescribed in detail.

Various embodiments of the present invention may be embodied in manydifferent forms and should not be construed as being limited to theexample embodiments set forth herein. Rather, these example embodimentsof the disclosure are provided so that this disclosure will be thoroughand complete and will convey inventive concepts of the disclosure tothose skilled in the art.

In the accompanying drawings, sizes or thicknesses of various componentsare exaggerated for brevity and clarity. Like numbers refer to likeelements throughout. As used herein, the term “and/or” includes any andall combinations of one or more of the associated listed items. Inaddition, it will be understood that when an element A is referred to asbeing “connected to” an element B, the element A can be directlyconnected to the element B or an intervening element C may be presentand the element A and the element B are indirectly connected to eachother.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprise or include” and/or“comprising or including,” when used in this specification, specify thepresence of stated features, numbers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, numbers, steps, operations, elements,components, and/or groups thereof.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various members, elements, regions, layersand/or sections, these members, elements, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one member, element, region, layer and/or section fromanother. Thus, for example, a first member, a first element, a firstregion, a first layer and/or a first section discussed below could betermed a second member, a second element, a second region, a secondlayer and/or a second section without departing from the teachings ofthe present disclosure.

Spatially relative terms, such as “below,” “beneath,” “lower,” “above,”“upper,” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “on” or “above” the otherelements or features. Thus, the exemplary term “below” can encompassboth an orientation of above and below.

In addition, as used herein, the term “separator” includes a separatorgenerally used in liquid electrolyte batteries using a liquidelectrolyte having a low affinity to the separator. Further, as usedherein, the term “separator” may include an intrinsic solid polymerelectrolyte in which the electrolyte is strongly bound to the separatorto then be recognized as being the same as the separator, and/or a gelsolid polymer. Therefore, the meaning of the separator should be definedas specifically defined in the specification of the present disclosure.

Referring to FIGS. 1A, 1B and 1C, a perspective view, a cross-sectionalview and an exploded perspective view of a secondary battery accordingto an embodiment of the present invention are illustrated.

As shown in FIGS. 1A, 1B and 1C, the secondary battery 100 according toan embodiment of the present invention may include a case 110, first andsecond electrode assemblies 120A and 120B, a cap plate 130, a firstelectrode terminal 140 and a second electrode terminal 150.

The case 110 may be made of a conductive metal, such as aluminum, analuminum alloy or nickel plated steel, and may be substantially shapedof a hexahedron having an opening through which the electrode assemblies120A and 120B can be inserted into the case 110. While the opening isnot shown in FIG. 1B because the case 110 and the cap plate 130 areassembled with each other, it may be a substantially opened part of atop portion of the case 110. Meanwhile, since the internal surface ofthe case 110 is insulated, the case 110 may be insulated from the firstand second electrode assemblies 120A and 120B. Here, the case 110 mayalso referred to as a can in some instances.

The case 110 may include a first long side portion 111 having arelatively large area, a second long side portion 112 facing the firstlong side portion 111 and having a relatively large area, a first shortside portion 113 connecting first ends of the first and second long sideportions 111 and 112 and having a relatively small area, a second shortside portion 114 facing the third short side portion 113, connectingsecond ends of the first and second long side portions 111 and 112 andhaving a relatively small area, and a bottom portion 115 connecting thefirst and second long side portions 111 and 112 and the first and secondshort side portions 113 and 114.

The first electrode assembly 120A is assembled inside the case 110.Particularly, one surface of the first electrode assembly 120A iscoupled to the case 110 in a state in which it is brought into closecontact/contact with the first long side portion 111 of the case 110.The first electrode assembly 120A may be manufactured by winding orlaminating a stacked structure including a first electrode plate 121, aseparator 122, and a second electrode plate 123, which are thin platesor layers. Here, the first electrode plate 121 may operate as a positiveelectrode and the second electrode plate 123 may operate as a negativeelectrode. Of course, polarities of the first electrode plate 121 andthe second electrode plate 123 may be reversed. In addition, if thefirst electrode assembly 120A is manufactured in a winding type, a firstwinding center 125A (or a first winding leading edge) where winding isstarted may be located at the center of the first electrode assembly120A.

The first electrode plate 121 may include a first current collectorplate 121 a made of a metal foil or mesh including aluminum or analuminum alloy, a first coating portion 121 b having a firstelectrically active material, such as a transition metal oxide, on thefirst current collector plate 121 a, a first non-coating portion (or afirst uncoated portion) 121 c on which the first electrically activematerial is not coated, and a first electrode first multi-tab 161outwardly (or upwardly) extended from the first non-coating portion 121c and electrically connected to the first electrode terminal 140. Here,the first electrode first multi-tab 161 may become a passageway of theflow of current between the first electrode plate 121 and the firstelectrode terminal 140 and may include multiple first electrode firsttabs arranged in a stacked type to be referred to as multi-tabs. Inaddition, the first electrode first multi-tab 161 may be provided suchthat the first non-coating portion 121 c is upwardly extended/protruded.Here, the first electrode may be a positive electrode.

The second electrode plate 123 may include a second current collectorplate 123 a made of a metal foil or mesh including copper, a copperalloy, nickel or a nickel alloy, a second coating portion 123 b having asecond electrically active material, such as graphite or carbon, on thesecond current collector plate 123 a, a second non-coating portion (or asecond uncoated portion) 123 c on which the second electrically activematerial is not coated, and a second electrode first multi-tab 171outwardly (or upwardly) extended from the second non-coating portion 123c and electrically connected to the second electrode terminal 150. Here,the second electrode first multi-tab 171 may become a passageway of theflow of current between the second electrode plate 123 and the secondelectrode terminal 150 and may include multiple second electrode firsttabs arranged in a stacked type to be referred to as multi-tabs. Inaddition, the second electrode first multi-tab 171 may be provided suchthat the second non-coating portion 123 c is upwardlyextended/protruded. Here, the second electrode may be a negativeelectrode.

The separator 122 may be positioned between the first electrode plate121 and the second electrode plate 123 to prevent an electrical shortcircuit from occurring between the first electrode plate 121 and thesecond electrode plate 123 and to allow movement of lithium ions. Theseparator 122 may include polyethylene, polypropylene or a compositefilm of polyethylene and polypropylene. However, the material of theseparator 122 is not limited to the specific materials listed herein. Inaddition, if an inorganic solid electrolyte is used, the separator 122may not be provided.

The second electrode assembly 120B may have substantially the samestructure, type and/or material as those of the first electrode assembly120A. Therefore, detailed descriptions of the second electrode assembly120B will be omitted. However, one surface of the second electrodeassembly 120B is coupled to the case 110 in a state in which it isbrought into close contact/contact with the second long side portion 112of the case 110. In addition, if the second electrode assembly 120B ismanufactured in a winding type, a second winding center 125B (or asecond winding leading edge) where winding is started may be located atthe center of the second electrode assembly 120B.

In addition, the first and second electrode assemblies 120A and 120Binclude a boundary area where the first and second electrode assemblies120A and 120B face each other inside the case 110 or a contact area 190where the first and second electrode assemblies 120A and 120B arebrought into close contact/contact with each other. That is to say, thefirst and second electrode assemblies 120A and 120B may be assembledinside the case 110 in a state in which they are brought into closecontact/contact with each other.

Meanwhile, the second electrode assembly 120B may include a firstelectrode second multi-tab 162 outwardly (or upwardly) extended from thefirst electrode plate 121 and electrically connected to the firstelectrode terminal 140. Here, the first electrode second multi-tab 162may become a passageway of the flow of current between the firstelectrode plate 121 and the first electrode terminal 140 and may includemultiple first electrode second tabs arranged in a stacked type to bereferred to as multi-tabs. In addition, the first electrode secondmulti-tab 162 may be provided such that the first non-coating portion121 c is upwardly extended/protruded.

In addition, the second electrode assembly 120B may include a secondelectrode second multi-tab 172 outwardly (or upwardly) extended from thesecond electrode plate 123 and electrically connected to the secondelectrode terminal 150. Here, the second electrode second multi-tab 172may become a passageway of the flow of current between the secondelectrode plate 123 and the second electrode terminal 150 and mayinclude multiple second electrode second tabs arranged in a stacked typeto be referred to as multi-tabs. In addition, the second electrodesecond multi-tab 172 may be provided such that the second non-coatingportion 123 c is upwardly extended/protruded.

Meanwhile, an axis of each of the first and second winding centers 125Aand 125B of the first and second electrode assemblies 120A and 120B,that is, a winding axis, is substantially parallel or horizontal to aterminal axis of each of the first and second electrode terminals 140and 150. Here, the winding axis and the terminal axis may mean anup-and-down axis in FIGS. 1B and 1C, and the expression “the windingaxis and the terminal axis being substantially parallel or horizontal toeach other” may mean that the winding axis and the terminal axis may notmeet each other even if the winding axis and the terminal axis areextended or may meet each other when the winding axis and the terminalaxis are extraordinarily extended.

In addition, as described above, the first and second multi-tabs 161 and162 extended and bent a predetermined length are positioned between thefirst and second electrode assemblies 120A and 120B and the firstelectrode terminal 140, and the first and second multi-tabs 171 and 172extended and bent a predetermined length are positioned between thefirst and second electrode assemblies 120A and 120B and the secondelectrode terminal 150. That is to say, the first and second multi-tabs161 and 162 located at one side may be extended and bent from top endsof the first and second electrode assemblies 120A and 120B toward thefirst electrode terminal 140 so as to be substantially symmetrical witheach other to then be connected or welded to the first electrodeterminal 140. In addition, the first and second multi-tabs 171 and 172located at the other side may also be extended and bent from the topends of the first and second electrode assemblies 120A and 120B towardthe second electrode terminal 150 so as to be substantially symmetricalwith each other to then be connected or welded to the second electrodeterminal 150.

Substantially, each of the first and second multi-tabs 161 and 162located at one side may be the first non-coating portion 121 c itself,which is a region of the first electrode plate 121, without a firstactive material coated thereon, or may be a separate member connected tothe first non-coating portion 121 c. Here, the separate member may bemade of one selected from the group consisting of aluminum, an aluminumalloy, nickel, a nickel alloy, copper, a copper alloy, and equivalentsthereof.

In addition, each of the first and second multi-tabs 171 and 172 locatedat the other side may be the second non-coating portion 123 c itself,which is a region of the second electrode plate 123, without a secondactive material coated thereon, or may be a separate member connected tothe second non-coating portion 123 c. Here, the separate member may bemade of one selected from the group consisting of nickel, a nickelalloy, copper, a copper alloy, aluminum, an aluminum alloy, andequivalents thereof.

As described above, since the first and second winding axes of the firstand second electrode assemblies 120A and 120B and the terminal axes ofthe first and second electrode terminals 140 and 150 are substantiallyparallel or horizontal to each other, as described above, an electrolyteinjection direction and the winding axes are also substantially parallelor horizontal to each other. Therefore, the first and second electrodeassemblies 120A and 120B exhibit high electrolyte impregnationcapability when an electrolyte is injected and internal gases arerapidly transferred to a safety vent 136 during over-charge, enablingthe safety vent 136 to quickly operate.

In addition, the first and second multi-tabs 161/171 and 162/172 (oruncoated portions or separate members) of the first and second electrodeassemblies 120A and 120B are extended and bent to be are directlyelectrically connected to the first and second electrode terminals 140and 150, which shortens electrical paths, thereby reducing internalresistance of the secondary battery 100 while reducing the number ofcomponents of the secondary battery 100.

In particular, since the first and second multi-tabs 161/171 and 162/172(or uncoated portions or separate members) of the first and secondelectrode assemblies 120A and 120B are directly electrically connectedto first and second electrode terminals 140 and 150 while beingsymmetrical with each other, unnecessary electrical short circuitsbetween the first and second multi-tabs 161/171 and 162/172 and regionshaving polarities opposite to the first and second multi-tabs 161/171 or162/172 (e.g., the case, cap plate and/or predetermined portions of thefirst and second electrode assemblies 120A and 120B can be prevented. Inother words, insulation levels of the first and second multi-tabs161/171 and 162/172 can be improved by the symmetrical structure of thefirst and second multi-tabs 161/171 and 162/172.

The first and second electrode assemblies 120A and 120B may beaccommodated in the case 110 together with an electrolyte. Theelectrolyte may include an organic solvent, such as ethylene carbonate(EC), propylene carbonate (PC), diethyl carbonate (DEC), ethylmethylcarbonate (EMC), or dimethyl carbonate (DMC), and a lithium salt such asLiPF₆ or LiBF₄. In addition, the electrolyte may be in a liquid, sold orgel phase.

The cap plate 130 may be substantially shaped of a rectangle havinglengths and widths and may be coupled to the case 110. That is to say,the cap plate 130 may seal an opening of the case 110 and may be made ofthe same material as the case 110. For example, the cap plate 130 may becoupled to the case 110 by laser and/or ultrasonic welding. Here, thecap plate 130 may also be referred to as a cap assembly in someinstances.

The cap plate 130 may include a plug 134 closing an electrolyteinjection hole, and a safety vent 136 clogging a vent hole. In addition,the safety vent 136 may include a notch configured to be easily openedat a preset pressure.

The first electrode terminal 140 may include a first electrode terminalplate 141 positioned on a top surface of the cap plate 130, a firstupper insulation plate 142 positioned between the first electrodeterminal plate 141 and the cap plate 130, a first lower insulation plate143 positioned on a bottom surface of the cap plate 130, a first currentcollector plate 144 positioned on a bottom surface of the first lowerinsulation plate 143, and a first electrode terminal pillar 145electrically connecting the first electrode terminal plate 141 and thefirst current collector plate 144. In addition, the secondary battery100 according to an embodiment of the present invention may furtherinclude a first seal insulation gasket 146 insulating the cap plate 130and the first electrode terminal pillar 145 from each other.

Here, the first and second multi-tabs 161 and 162 of the first andsecond electrode assemblies 120A and 120B may be electrically connectedto the first current collector plate 144 of the first electrode terminal140 so as to be symmetrical with each other.

The second electrode terminal 150 may include a second electrodeterminal plate 151 positioned on the top surface of the cap plate 130, asecond upper insulation plate 152 positioned between the secondelectrode terminal plate 151 and the cap plate 130, a second lowerinsulation plate 153 positioned on the bottom surface of the cap plate130, a second current collector plate 154 positioned on a bottom surfaceof the second lower insulation plate 153, and a second electrodeterminal pillar 145 electrically connecting the second electrodeterminal plate 151 and the second current collector plate 154. Inaddition, the secondary battery 100 according to an embodiment of thepresent invention may further include a second seal insulation gasket156 insulating the cap plate 130 and the second electrode terminalpillar 155 from each other.

Here, the first and second multi-tabs 171 and 172 of the first andsecond electrode assemblies 120A and 120B may be electrically connectedto the second current collector plate 154 of the second electrodeterminal 150 so as to be symmetrical with each other.

Meanwhile, in an embodiment of the present invention, an insulationplate 180 is further positioned between each of the first and secondelectrode assemblies 120A and 120B, the first and second multi-tabs161/171 and 162/172 and the first and second electrode terminals 140 and150, thereby preventing the first and second multi-tabs 161/171 or162/172 and regions having polarities opposite to the first and secondmulti-tabs 161/171 or 162/172 (e.g., the case, the cap plate and/or thepredetermined regions of the first and second electrode assemblies) frombeing electrically short-circuited to each other. The insulation plate180 may be made of, for example, but not limited to, a super engineeringplastic, such as polyphenylene sulfide (PPS), having excellent dimensionstability and maintaining a high strength and stiffness up toapproximately 220° C.

As described above, in the secondary battery 100 according to theembodiment of the present invention, the first and second multi-tabs161/171 and 162/172 of the first and second electrode assemblies 120Aand 120B are configured such that they are extended and bent to besymmetrical with each other with respect to the boundary area (orcontact area) 190 between the first and second electrode terminals 140and 150 or the first and second electrode assemblies 120A and 120B),thereby preventing the first and second multi-tabs 161/171 or 162/172and the regions having polarities opposite to the first and secondmulti-tabs 161/171 or 162/172 (e.g., the case 110, the cap plate 130and/or the predetermined regions of the first and second electrodeassemblies 120A and 120B) from being electrically short-circuited toeach other.

That is to say, if the first and second multi-tabs 161/171 and 162/172are configured to be symmetrical with each other with respect to theboundary area 190 between the first and second electrode terminals 140and 150 or the first and second electrode assemblies 120A and 120B, aprobability of electrical short circuits occurring between the first andsecond multi-tabs 161/171 and 162/172 and the case 110, the cap plate130 and/or the predetermined regions of the first and second electrodeassemblies 120A and 120B having polarities opposite to the first andsecond multi-tabs 161/171 or 162/172, may be increased. However, like inthe embodiment of the present invention, if the first and secondmulti-tabs 161 and 162 are configured to be symmetrical with each other,the probability of occurrence of such electrical short circuits can bereduced.

For example, a probability of electrical short circuits occurringbetween the positive electrode first and second multi-tabs 161 and 162configured to be symmetrical with each other and the negative electrodenon-coating portions 123 c of the first and second electrode assemblies120A and 120B, is smaller than a probability of electrical shortcircuits occurring between positive electrode first and secondmulti-tabs configured to be asymmetrical with each other and negativeelectrode non-coating portions of first and second electrode assemblies,but aspects of the present invention are not limited thereto. Inaddition, for example, a probability of electrical short circuitsoccurring between the negative electrode first and second multi-tabs 171and 172 configured to be symmetrical with each other and the positiveelectrode non-coating portions 121 c of the first and second electrodeassemblies 120A and 120B, is smaller than a probability of electricalshort circuits occurring between negative electrode first and secondmulti-tabs configured to be asymmetrical with each other and positiveelectrode non-coating portions of first and second electrode assemblies,but aspects of the present invention are not limited thereto.

In other words, if the first and second multi-tabs 161/171 and 162/172of the first and second electrode assemblies 120A and 120B areconfigured to be symmetrical with each other, the number or area ofmanagement regions for preventing electrical short circuits between thefirst and second multi-tabs 161/171 or 162/172 and the regions havingopposite polarities, that is, the case 110, the cap plate 130 and/or thepredetermined regions of the first and second electrode assemblies 120Aand 120B, may be reduced. Accordingly, the electrical short circuitsbetween the first and second multi-tabs 161/171 and 162/172 and theregions having the opposite polarities can be easily prevented. However,if the first and second multi-tabs 161/171 and 162/172 of the first andsecond electrode assemblies 120A and 120B are configured to beasymmetrical with each other, the number or area of management regionsfor preventing electrical short circuits between the first and secondmulti-tabs 161/171 or 162/172 and the regions having oppositepolarities, may be increased. Accordingly, it is difficult to preventthe electrical short circuits between the first and second multi-tabs161/171 and 162/172 and the regions having the opposite polarities.

Referring to FIGS. 2A and 2B, a plan view and a partial cross-sectionalview of first and second electrode assemblies in a secondary batteryhaving a structure for suppressing multi-tab short circuits according toan embodiment of the present invention are illustrated.

As shown in FIGS. 2A and 2B, the first electrode assembly 120A mayinclude a first winding center 125A (or a first winding leading edge)where winding is started, and the second electrode assembly 120B mayalso include a second winding center 125B (or a second winding leadingedge) where winding is started. In addition, the first and secondelectrode assemblies 120A and 120B may have a boundary area (or contactarea) 190) therebetween.

In the following description, outer regions of the first and secondelectrode assemblies 120A and 120B may mean regions spaced apart fromthe boundary area 190 between the first and second electrode assemblies120A and 120B and closer to the first and second long side portions 111or 112 of the case 110, and inner regions of the first and secondelectrode assemblies 120A and 120B may mean regions spaced apart fromthe first and second long side portions 111 or 112 of the case 110 andcloser to the boundary area 190 between the first and second electrodeassemblies 120A and 120B. In addition, in the following description, theouter regions of the first and second electrode assemblies 120A and 120Bmay mean regions from the first and second winding centers 125A or 1256to the first and second long side portions 111 or 112 of the case 110,and the inner regions of the first and second electrode assemblies 120Aand 120B may mean regions from the first and second winding centers 125Aor 125B to the boundary area 190 between the first and second electrodeassemblies 120A and 120B. It should be understood that definitions ofthe outer and inner regions of the first and second electrode assemblies120A and 120B can be commonly applied to all embodiments of the presentinvention.

As shown in FIG. 2A, the first and second electrode assemblies 120A and120B may include the first and second multi-tabs 161/162 or 171/172located at their outer regions so as to be symmetrical with each otherwith respect to the boundary area 190. The first multi-tabs 161 and 171may be located only at, for example, but not limited to, the outerregion of the first electrode assembly 120A. That is to say, the firstmulti-tabs 161 and 171 may not be located at the inner regions of thefirst electrode assembly 120A. In addition, the second multi-tabs 162and 172 may also be located only at the outer regions of the secondelectrode assembly 120B. That is to say, the second multi-tabs 162 and172 may not be located at the inner regions of the second electrodeassembly 120B. More specifically, as shown in FIG. 2A, the firstmulti-tabs 161 and 171 may be located only at roughly upper regions ofthe first winding center 125A in the first electrode assembly 120A(i.e., regions adjacent to the first long side portion 111 of the case110), and the second multi-tabs 162 and 172 may be located only atroughly lower regions of the second winding center 125B in the secondelectrode assembly 120B (i.e., regions adjacent to the second long sideportion 112 of the case 110). Therefore, the maximum distance betweenthe first and second multi-tabs 161/162 or 171/172 may be equal to orslightly smaller than the maximum overall width (or thickness) of thefirst and second electrode assemblies 120A and 120B.

In addition, as shown in FIG. 2B, the first and second electrodeassemblies 120A and 120B may include the first and second multi-tabs 161and 162 extended and bent from the outer regions so as to be symmetricalwith each other with respect to the boundary area 190 or the electrodeterminal 140. The first and second multi-tabs 161 and 162 may beextended and bent from, for example, but not limited to, the outerregions of the first and second electrode assemblies 120A and 120B tothe electrode terminal 140 so as to be symmetrical with each other withrespect to the boundary area 190. In other words, the first and secondmulti-tabs 161 and 162 may be extended and bent to the electrodeterminal 140 from regions closer to the case 110 (i.e., the first longside portion or the second long side portion) than to the boundary area190 between the first and second electrode assemblies 120A and 120B,respectively.

Still in other words, the first and second multi-tabs 161 and 162 mayinclude first regions 161 a and 162 a extended from the outer regions ofthe first and second electrode assemblies 120A and 120B, second regions161 b and 162 b extended from the first regions 161 a and 162 a to beadjacent to the case 110, and third regions 161 c and 162 c bent fromthe second regions 161 b and 162 b to be electrically connected to theelectrode terminal 140, respectively.

Here, as the first regions 161 a and 162 a get closer from the case 110(i.e., the first long side portion or the second long side portion) tothe boundary area 190 between the first and second electrode assemblies120A and 120B, bending angles of the first regions 161 a and 162 a aremore increased. In addition, the second regions 161 b and 162 b may besubstantially parallel with a longitudinal direction of the case 110(i.e., the first long side portion or the second long side portion). Inaddition, the third regions 161 c and 162 c may be connected to theelectrode terminal 140 while being bent roughly at right angle from thesecond regions 161 b and 162 b.

In addition, since the insulation plate 180 is further located betweenthe first and second electrode assemblies 120A and 120B and the firstand second multi-tabs 161 and 162, and the electrode terminal 140,electrical short circuits may not occur between the first and secondmulti-tabs 161 and 162, and the case, the cap plate and/or thepredetermined regions of the first and second electrode assemblies,which have polarities opposite to the first and second multi-tabs 161and 162. In particular, the insulation plate 180 is placed roughly onthe separator 122 of each of the first and second electrode assemblies120A and 120B.

As described above, according to the embodiment of the presentinvention, the first and second multi-tabs 161 and 162 are extended andbent from the outer regions of the first and second electrode assemblies120A and 120B to the electrode terminal 140 so as to be symmetrical witheach other with respect to the electrode terminal 140 or the boundaryarea 190 between the first and second electrode assemblies 120A and120B, thereby suppressing electrical short circuits between the firstand second multi-tabs 161 and 162 and the regions having polaritiesopposite thereto (e.g., the case, the cap plate and/or the predeterminedregions of the first and second electrode assemblies).

Referring to FIGS. 3A and 3B, a plan view and a partial cross-sectionalview of first and second electrode assemblies in a secondary batteryhaving a structure for suppressing multi-tab short circuits according toanother embodiment of the present invention are illustrated.

As shown in FIG. 3A, the first and second electrode assemblies 120A and120B may include first and second multi-tabs 261/262 or 271/272 locatedat their inner regions so as to be symmetrical with each other withrespect to the boundary area 190 between the first and second electrodeassemblies 120A and 120B. The first multi-tabs 261 and 271 may belocated only at, for example, but not limited to, the inner regions ofthe first electrode assembly 120A. That is to say, the first multi-tabs261 and 271 may not be located at the outer regions of the firstelectrode assembly 120A. In addition, the second multi-tabs 262 and 272may also be located only at the inner regions of the second electrodeassembly 120B. That is to say, the second multi-tabs 262 and 272 may notbe located at the outer regions of the second electrode assembly 120B.More specifically, as shown in FIG. 3A, the first multi-tabs 261 and 271may be located only at roughly lower regions of the first winding center125A in the first electrode assembly 120A (i.e., regions adjacent to theboundary area 190), and the second multi-tabs 262 and 272 may be locatedonly at roughly upper regions of the second winding center 125B in thesecond electrode assembly 120B (i.e., regions adjacent to the boundaryarea 190). Therefore, the maximum distance between the first and secondmulti-tabs 261/262 or 271/272 may be equal to or slightly greater thanthe minimum distance between the first and second electrode assemblies120A and 120B.

In addition, as shown in FIG. 3B, the first and second electrodeassemblies 120A and 120B may include the first and second multi-tabs 261and 262 extended and bent from the inner regions so as to be symmetricalwith each other with respect to the boundary area 190 between first andsecond electrode assemblies 120A and 120B or the electrode terminal 140.The first and second multi-tabs 261 and 262 may be extended and bent,for example, but not limited to, from the inner regions of the first andsecond electrode assemblies 120A and 120B to the electrode terminal 140so as to be symmetrical with each other, respectively. In other words,the first and second multi-tabs 261 and 262 may be extended and bent tothe electrode terminal 140 from regions closer to the boundary area 190between the first and second electrode assemblies 120A and 120B than tothe first long side portion 111 or the second long side portion 112 ofthe case 110.

Still in other words, the first and second multi-tabs 261 and 262 mayinclude first regions 261 a and 262 a extended from the inner regions ofthe first and second electrode assemblies 120A and 120B, second regions261 b and 262 b extended from the first regions 261 a and 262 a to beadjacent to the case 110, and third regions 261 c and 262 c bent fromthe second regions 261 b and 262 b to be electrically connected to theelectrode terminal 140, respectively.

Here, as the first regions 261 a and 262 a get closer from the case 110to the boundary area 190 between the first and second electrodeassemblies 120A and 120B, bending angles of the first regions 261 a and262 a are more increased. In addition, the second regions 261 b and 262b may be substantially parallel with a longitudinal direction of thecase 110. In addition, the third regions 261 c and 262 c may beconnected to the electrode terminal 140 while being bent roughly atright angle from the second regions 261 b and 262 b.

In addition, since the insulation plate 180 is further located betweenthe first and second electrode assemblies 120A and 120B and the firstand second multi-tabs 261 and 262, and the electrode terminal 140,electrical short circuits may not occur between the first and secondmulti-tabs 261 and 262, and the case, the cap plate and/or thepredetermined regions of the first and second electrode assemblies,which have polarities opposite to the first and second multi-tabs 261and 262. In particular, the insulation plate 180 is placed roughly onthe first regions 261 a and 262 a of the first and second multi-tabs 261and 262.

As described above, according to the embodiment of the presentinvention, the first and second multi-tabs 261 and 262 are extended andbent from the inner regions of the first and second electrode assemblies120A and 120B to the electrode terminal 140 so as to be symmetrical witheach other with respect to the electrode terminal 140 or the boundaryarea 190 between the first and second electrode assemblies 120A and120B, thereby suppressing electrical short circuits between the firstand second multi-tabs 261 and 262 and the regions having polaritiesopposite thereto (e.g., the case, the cap plate and/or the predeterminedregions of the first and second electrode assemblies).

Referring to FIGS. 4A and 4B, a plan view and a perspective view offirst and second electrode assemblies in a secondary battery having astructure for suppressing multi-tab short circuits according to anotherembodiment of the present invention are illustrated.

As shown in FIGS. 4A and 4B, the first and second electrode assemblies120A and 120B may include first and second multi-tabs (or outermulti-tabs) 361 and 362 located at their outer regions and first andsecond multi-tabs (or inner multi-tabs) 371 and 372 located at theirinner regions.

For example, in FIGS. 4A and 4B, the first and second multi-tabs 361 and362 located roughly in the left sides of the first and second electrodeassemblies 120A and 120B may be symmetrical with outer regions (i.e.,regions each adjacent to a first long side portion or a second long sideportion) of the first and second electrode assemblies 120A and 120B, andthe first and second multi-tabs 371 and 372 located roughly in the rightsides of the first and second electrode assemblies 120A and 120B may besymmetrical with inner regions (i.e., regions each adjacent to theboundary area) of the first and second electrode assemblies 120A and120B. Here, the left-side first and second multi-tabs 361 and 362 may bepositive electrode tabs, and the right-side first and second multi-tabs371 and 372 may be negative electrode tabs.

In more detail, in the first electrode assembly 120A, the left-sidefirst multi-tab 361 (positive electrode) may be located at the outerregion of the first electrode assembly 120A, and the right-side firstmulti-tab 371 (negative electrode) may be located at the inner region ofthe first electrode assembly 120A. In the second electrode assembly120B, the left-side first multi-tab 362 (positive electrode) may belocated at the outer region of the second electrode assembly 120B, andthe right-side first multi-tab 372 (negative electrode) may be locatedat the inner region of the second electrode assembly 120B.

Still in other words, the first and second multi-tabs 361 and 362 of thefirst and second electrode assemblies 120A and 120B may be symmetricalwith each other, and the left-side first multi-tab 361 (positiveelectrode) and the right-side first multi-tab 371 (negative electrode)of the first electrode assembly 120A are extended and bent to besymmetrical with each other to then be coupled to the first and secondelectrode terminals 140 and 150, respectively. In addition, the firstand second multi-tabs 371 and 372 of the first and second electrodeassemblies 120A and 120B may be symmetrical with each other, and theleft-side second multi-tab 362 (positive electrode) and the right-sidesecond multi-tab 372 (negative electrode) of the second electrodeassembly 120B are extended and bent to be symmetrical with each other tothen be coupled to the first and second electrode terminals 140 and 150,respectively.

Therefore, the first electrode assembly 120A is coupled to the first andsecond electrode terminals 140 and 150, respectively, in a state inwhich the positive electrode first multi-tab 361 and the negativeelectrode first multi-tab 371 are symmetrical with each other, and thesecond electrode assembly 120B is coupled to the first and secondelectrode terminals 140 and 150, respectively, in a state in which thepositive electrode second multi-tab 362 and the negative electrodesecond multi-tab 372 are symmetrical with each other, thereby improvingcoupling strength, coupling stiffness and coupling reliability betweenthe first and second electrode assemblies 120A and 120B and the firstand second electrode terminals 140 and 150.

Referring to FIGS. 5A and 5B, enlarged cross-sectional viewsillustrating states before and after bending multi-tabs according to anembodiment of the present invention are illustrated. Here, FIG. 5A showsa state before bending the multi-tabs 161 of the electrode assembly120A. As shown in FIG. 5A, the multi-tabs 161 are directly extended informs of straight lines. In addition, FIG. 5B shows a state afterbending the multi-tabs 161 of the electrode assembly 120A by connectingthe multi-tabs 161 of the electrode assembly 120A to the electrodeterminal 140. As shown in FIG. 5B, the multi-tabs 161 are bent in aroughly L-shaped configuration.

As shown in FIGS. 5A and 5B, the electrode assembly 120A may include thefirst electrode plate 121, the separator 122 and the second electrodeplate 123, as described above.

Here, the first electrode plate 121 may have, for example, but notlimited to, a positive polarity, and may include a first currentcollector plate 121 a having a substantially planar first surface 121 dand a substantially planar second surface 121 e opposite to the firstsurface 121 d. In addition, the first electrode plate 121 may have afirst electrically active material layer 121 b coated on the firstsurface 121 d and/or the second surface 121 e of the first currentcollector plate 121 a.

The multi-tabs 161 may have, for example, but not limited to, astructure in which the first current collector plate 121 a or thenon-coating portion 121 c (see FIG. 1C) is upwardly extended to anexterior side of the first electrically active material layer 121 b ofthe first electrode plate 121. Therefore, the multi-tab 161 may alsohave a substantially planar first surface 161 d and a substantiallyplanar second surface 161 e opposite to the first surface 161 d. Inaddition, the first surface 121 d of the first current collector plate121 a and the first surface 161 d of the multi-tab 161 may besubstantially coplanar, and the second surface 121 e of the firstcurrent collector plate 121 a and the second surface 161 e of themulti-tab 161 may also be substantially coplanar. In addition, the firstcurrent collector plate 121 a and the multi-tabs 161 may havesubstantially the same thickness. Of course, in addition to theconfiguration stated above, the multi-tabs 161 may also be provided byattaching a separate member to the first current collector plate 121 aor the non-coating portion 121 c outwardly extended from the firstelectrically active material layer 121 b.

The separator 122 is positioned between the first electrode plate 121and the second electrode plate 123. A length (or height) of theseparator 122 may be greater than a length (or height) of the firstelectrode plate 121 and/or the second electrode plate 123. That is tosay, a top end of the separator 122 may be positioned higher than topends of the first electrode plate 121 and/or the second electrode plate123.

The second electrode plate 123 may have, for example, but not limitedto, a negative polarity. The second electrode plate 123 is located atone side of the separator 122 and may include a second current collectorplate 123 a having a substantially planar first surface 123 d and asubstantially planar second surface 123 e opposite to the first surface123 d, and a second electrically active material layer 123 b coated onthe first surface 123 d and/or the second surface 123 e of the secondcurrent collector plate 123 a. In addition, a safety function layer(SFL) 123 f allowing lithium ions to pass while blocking migrationelectrons may be further located on a surface of the second electricallyactive material layer 123 b. The SFL 123 f may be made of, for example,but not limited to, an inorganic material, such as ceramic, and maysuppress decomposition of electrolyte by blocking the electronmigration.

Here, the length (or height) of the second electrode plate 123 may begreater than that of the first electrode plate 121. Thus, excessivelithium ions or metallic ions may not exist inside the electrodeassembly 120A (particularly, on the surface of the second electricallyactive material layer). In addition, the length (or height) of theseparator 122 is largest, and the length (or height) of the firstelectrode plate 121, exclusive of the multi-tab 161, is smallest.

In addition, since the separator 122 is positioned between the multi-tab161 and the second electrode plate 123, the multi-tab 161 can beprevented from being directly electrically short-circuited to the secondelectrode plate 123 (e.g., the second current collector plate 123 a orthe second electrically active material layer 123 b) even if themulti-tab 161 is bent to be connected to the electrode terminal 140.

In addition, in the embodiment of the present invention, in order tomore efficiently suppress the multi-tab short circuit, insulating layers280 may be coated on surfaces of the multi-tabs 161. That is to say, theinsulating layers 280 may be coated on the first surface 161 d and/orthe second surface 161 e of the multi-tab 161. The insulating layers 280may be coated on the first surface 161 d and/or the second surface 161 ewhile being in contact with the first electrically active material layer121 b. Moreover, a topmost height of each of the insulating layers 280may be equal to, for example, a topmost height of each of the separators122. If the topmost height of the insulating layer 280 is smaller thanthat of the separator 122, the multi-tabs 161 may be at risk of beingbrought into direct contact with the second electrode plate 123 (e.g.,the second current collector plate 123 a, the second electrically activematerial layer 123 b, etc.) when they are bent. In addition, if thetopmost height of the insulating layer 280 is larger than that of theseparator 122, the insulation level of the multi-tab 161 is increased,but the insulating efficiency between the multi-tabs 161 and the secondelectrode plate 123 may not be improved any more.

A thickness of the insulating layer 280 may be smaller than a thicknessof the first electrically active material layer 121 b. The thickness ofthe first electrically active material layer 121 b may be in the rangefrom, for example, but not limited to, about 100 μm to about 600 μm, andthe thickness of the insulating layer 280 may be in the range from about0.1 μm to about 100 μm, preferably from about 1 μm to about 50 μm, morepreferably from about 3 μm to about 8 μm. If the thickness of theinsulating layer 280 is larger than that of the first electricallyactive material layer 121 b, the overall thickness of the electrodeassembly 120A may be increased as much as the thickness of theinsulating layer 280, and the multi-tabs 161 may not be properly bent.Moreover, when the multi-tabs 161 are bent, the insulating layers 280may be separated away from the multi-tabs 161.

As described above, a double insulating structure including theinsulating layer 280 and the separator 122 may be positioned between themulti-tabs 161 and the second electrode plate 123, thereby preventingelectrical short circuits between the multi-tabs 161 and the secondelectrode plate 123, that is, increasing the insulation level of themulti-tabs 161.

Moreover, a triple insulating structure including the insulating layer280, the separator 122 and the SFL 123 f may be positioned between themulti-tabs 161 and the second electrode plate 123, thereby moreefficiently preventing electrical short circuits between the multi-tabs161 and the second electrode plate 123. That is to say, the insulationlevel of the multi-tabs 161 may be further increased.

The insulating layer 280 may be made of, for example, but not limitedto, an organic material, an inorganic material, or an organic-inorganiccomposite (or hybrid) material, using one or a combination of processesselected from the group consisting of inkjet printing, coating, dipcoating, doctor blade, dry dipping, hydro thermal reaction, sol-gel,spraying, aerosol deposition, chemical vapor deposition, physical vapordeposition, roll to roll, casting, an ion beam deposition, andequivalents thereof.

In addition, the organic material (or binder) may include, for example,but not limited to, one or a mixture of materials selected from thegroup consisting of polyimide (PI), polyamideimide (PA), polyvinylidenefluoride (PVdF), polyurethane (PU), polyurea, polycarbonate (PC),polyethylene terephthalate (PET) polymethyl methacrylate (PMMA),polybutylene terephthalate (PBT), polyvinyl alcohol (PVA), polyvinylbutyral (PVB) and equivalents thereof.

In addition, the inorganic may include, for example, but not limited to,one or a mixture of two materials selected from the group consisting ofalpha alumina (α-Al2O3), alumina (Al2O3), aluminum hydroxide (Al(OH)3,bohemite), lead zirconate titanate (Pb(Zr,Ti)O3(PZT)), titanium dioxide(TiO₂), zirconia (ZrO₂), yttria (Y₂O₃), yttria stabilized zirconia(YSZ), dysprocia (Dy₂O₃), gadolinia (Gd₂O₃), ceria (CeO₂), gadoliniadoped ceria (GDC), magnesia (MgO), barium titanate (BaTiO₃), nickelmanganite (NiMn₂O₄), potassium sodium niobate (KNaNbO₃), bismuthpotassium titanate (BiKTiO₃), bismuth sodium titanate (BiNaTiO₃),bismuth ferrite (BiFeO₃), bismuth zinc niobate (Bi₁₋₅Zn₁Nb_(1.5)O₇),tungsten oxide (WO), tin oxide (SnO2), lanthanum-strontium-manganeseoxide (LSMO), lanthanum-strontium-iron-cobalt oxide (LSFC), aluminumnitride (AlN), silicon nitride (SiN), silicon oxide (SiO2), zinc oxide(ZnO), hafnia (HfO2), titanium nitride (TiN), silicon carbide (SiC),titanium carbide (TiC), tungsten carbide (WC), magnesium boride (MgB),titanium boride (TiB), calcium oxide (CaO), cobalt ferrite (CoFe2O4),nickel ferrite (NiFe2O4), barium ferrite (BaFe2O4), nickel zinc ferrite(NiZnFe2O4), zinc ferrite (ZnFe2O4), manganese cobalt spinel oxideMnxCo3-xO4 (where x is a positive real number 3 or less), a mixture ofmetal oxide and metal nitride, a mixture of metal oxide and metalcarbide, a mixture of ceramic and polymer, a mixture of ceramic andmetal, and equivalents thereof.

In addition, the average particle diameter of the inorganic material maybe in the range from, for example, but not limited to, about 0.1 μm toabout 100 μm, preferably from about 0.3 μm to about 10 μm, morepreferably from about 0.5 μm to about 5 μm.

Meanwhile, in order to allow the multi-tabs 161 to be electricallyconnected to the electrode terminal 140, the multi-tabs 161 are bent ina roughly L-shaped configuration. Or after the multi-tabs 161 areconnected to the electrode terminal 140, the multi-tabs 161 are bent ina roughly L-shaped configuration. Here, since the multi-tabs 161 arebent while being in close contact with each other, not only themulti-tabs 161 but also the separator 122 and/or the second electrodeplate 123 are bent at a predetermined angle. In particular, theseparators 122 are bent with the multi-tabs 161, as shown in FIG. 5B.Here, since the insulating layers 280 are coated on the surfaces of themulti-tabs 161, as described above, the insulating layers 280 are alsobent.

Therefore, the multi-tabs 161 and the insulating layers 280 are broughtinto contact with/close contact with the separator 122 while being bent.Although FIG. 5B shows that the multi-tabs 161, the separator 122 andthe second electrode plate 123 are spaced apart from one another, theymay be substantially brought into contact/close contact with oneanother. Here, the electrical short circuits can be prevented fromoccurring between the multi-tabs 161 and the and the second electrodeplate 123 (i.e., the second current collector plate 123 a and/or thesecond electrically active material layer 123 b) by the doubleinsulating structure including the insulating layer 280 and theseparator 122, or the triple insulating structure including theinsulating layer 280, the separator 122 and the SFL 123 f, positionedbetween the multi-tab 161 and the second electrode plate 123.

In order to more improve the insulation efficiency, the insulating layer280 that is the same as described may be located on the surface of thesecond current collector plate 123 a exposed through the secondelectrically active material layer 123 b. Therefore, a triple insulatingstructure including the insulating layer 280, the separator 122 and theinsulating layer 280 may be provided between the multi-tabs 161 and thesecond current collector plate 123 a, thereby improving the insulatingefficiency between the multi-tabs 161 and the second current collectorplate 123 a.

Meanwhile, the mutual relationships, materials, types and configurationsof the insulating layers 280, the first electrode plate 121, theseparators 122 and the second electrode plate 123 located on themulti-tabs 161 can be commonly applied to all embodiments of the presentinvention.

FIGS. 6A and 6B are enlarged cross-sectional views illustrating statesbefore and after bending multi-tabs according to another embodiment ofthe present invention.

As shown in FIGS. 6A and 6B, insulating layers 380 formed on surfaces ofthe multi-tab 161 may be spaced apart a predetermined distance apartfrom the first electrically active material layer 121 b. That is to say,the insulating layers 380 may not be necessarily brought into directcontact with the first electrically active material layer 121 b but maybe located only on areas needed to be insulated.

In more detail, the insulating layers 380 may be located only atpredetermined areas of the multi-tabs 161 facing (corresponding to) atop end of the second electrode plate 123 spaced apart from the firstelectrically active material layer 121 b. That is to say, the insulatinglayers 380 may be located only at predetermined areas of the multi-tabs161, where the multi-tabs 161 are not electrically short-circuited tothe second electrode plate 123 even if the separator 122 is punched bybent regions of the multi-tabs 161 at the time of bending the multi-tabs161.

The insulating layers 380 may be spaced, for example, but not limitedto, about 0.1 mm to about 3 mm from the first electrically activematerial layer 121 b.

As described above, since the insulating layers 380 are located only atthe predetermined areas of the multi-tabs 161 spaced apart from thefirst electrically active material layer 121 b, the manufacturingprocess of the multi-tabs 161 can be facilitated. That is to say, theinsulating layers 380 are located on a non-coating portion of anelectrode plate, followed by performing a notching process using a laserbeam or a mold, thereby providing the multi-tabs 161. As describedabove, since the insulating layers 380 are located only at thepredetermined areas of the multi-tabs 161, electrical/mechanical loadsduring the notching process using a laser beam or a mold can be reduced,thereby facilitating the manufacturing process.

FIGS. 7A and 7B are enlarged cross-sectional views of multi-tabsaccording to another embodiment of the present invention.

As shown in FIG. 7A, each of the multi-tabs 161 may have a substantiallyplanar first surface 161 d, a substantially planar second surface 161 eopposite to the first surface 161 d, a third surface 161 f connectingfirst ends of the first and second surfaces 161 d and 161 e, and afourth surface 161 g connecting second ends of the first and secondsurfaces 161 d and 161 e and opposite to the third surface 161 f. Theinsulating layers 280 may be located only on the first and secondsurfaces 161 d and 161 e, which are relatively wide surfaces. That is tosay, the third and fourth surfaces 161 f and 161 g of the multi-tab 161may be exposed.

In other words, the insulating layers 280 are located on first andsecond surfaces of the non-coating portion, and the multi-tabs 161 arethen formed by performing the notching (or cutting) process using alaser beam or a mold. Therefore, as described above, the insulatinglayers 280 may not be located on the third and fourth surfaces 161 f and161 g of the multi-tab 161 but may be exposed. That is to say, onesurface of each of the insulating layers 280 may be coplanar with thethird surface 161 f of the multi-tab 161, and the other surface of theinsulating layer 280 may be coplanar with the fourth surface 161 g ofthe multi-tab 161.

Meanwhile, as shown in FIG. 7B, the insulating layers 280 may be locatednot only on the first and second surfaces 161 d and 161 e, which arerelatively wide surfaces, but also on the third and fourth surfaces 161f and 161 g, which are relatively narrow surfaces. That is to say, noneof the first, second, third and fourth surfaces 161 d, 161 e, 161 f and161 g of the multi-tab 161 may be exposed through the insulating layers280.

In other words, the insulating layers 280 are located on the first andsecond surfaces of the non-coating portion, and the multi-tabs 161 arethen formed by performing the notching (or cutting) process using alaser beam or a mold. Therefore, as described above, the insulatinglayers 280 may be located not only on the first and second surfaces 161d and 161 e but also on the third and fourth surfaces 161 f and 161 g ofthe multi-tab 161. That is to say, during the notching process using amold, a portion of the insulating layer 280 located on the first surface161 d or the second surface 161 e is pushed to the third and fourthsurfaces 161 f and 161 g, so that the third and fourth surfaces 161 fand 161 g of the multi-tab 161 are covered by the insulating layer 280.The insulating layers 280 located on the third and fourth surfaces 161 fand 161 g of the multi-tab 161 can also prevent electrical shortcircuits from occurring between the third and fourth surfaces 161 f and161 g and the second electrode plate 123 through the above-describedprocess.

Although the foregoing description has been made with regard to a casewhere the insulating layers 280 are formed on the surfaces of themulti-tabs 161, it should be understood by one skilled in the art thatthe insulating layers 280 are located on the surfaces of the first andsecond multi-tabs 161/171 and/or 162/172. Moreover, it should beunderstood by one skilled in the art that these features can be commonlyapplied to all embodiments of the present invention.

Referring to FIGS. 8A to 8C, schematic views illustrating amanufacturing method of a secondary battery 100 having a structure forsuppressing multi-tab short circuits according to an embodiment of thepresent invention are illustrated.

As shown in FIG. 8A, the first electrode first multi-tab 161 and thesecond electrode first multi-tab 171 of the first electrode assembly120A are welded to the first electrode terminal 140, that is, the firstcurrent collector plate 144, and the second electrode terminal 150, thatis, the second current collector plate 154, provided in the cap plate130, and the first electrode second multi-tab 162 and the secondelectrode second multi-tab 172 of the second electrode assembly 120B arealso welded to the first electrode terminal 140 and the second electrodeterminal 150, respectively. Here, the first electrode first multi-tab161 and the second electrode first multi-tab 171 of the first electrodeassembly 120A, and the first electrode second multi-tab 162 and thesecond electrode second multi-tab 172 of the second electrode assembly120B, have yet to be bent. In addition, if the welding process iscompleted, the insulation plate 180 is placed on the cap plate 130. Thatis to say, the insulation plate 180 is placed on the first electrodefirst multi-tab 161 and the first electrode second multi-tab 162, whichare positioned on the first current collector plate 144, and the secondelectrode first multi-tab 171 and second electrode second multi-tab 172,which are positioned on the second current collector plate 154.

As shown in FIG. 8B, the first and second electrode assemblies 120A and120B are bent roughly at right angle from the cap plate 130.Accordingly, the first and second multi-tabs 161 and 162 provided in thefirst and second electrode assemblies 120A and 120B are bent with thefirst regions 161 a and 162 a, the second regions 161 b and 162 b andthe third regions 161 c and 162 c. In addition, as the result of thebending process, the insulation plate 180 may be substantially coveredby the first and second electrode assemblies 120A and 120B, the firstand second multi-tabs 161 and 162 and the cap plate 130. In addition, asthe result of the bending process, the first and second electrodeassemblies 120A and 120B are brought into close contact with each otherto be parallel with each other.

As shown in FIG. 8C, the first and second electrode assemblies 120A and120B being in close contact with each other are inserted into the case110. That is to say, until the cap plate 130 closes the case 110, thefirst and second electrode assemblies 120A and 120B and the cap plate130 are pushed into the case 110.

Next, the cap plate 130 is welded to the case 110 to then be fixed, andan electrolytic solution is inserted into the case 110 through anelectrolyte injection hole. However, this process may be omitted in acase of a solid battery requiring no electrolytic solution.

Here, as described above, according to various embodiments of thepresent invention, since the first and second multi-tabs 161 and 162 arelocated only at outer regions (or inner regions) of the first and secondelectrode assemblies 120A and 120B, as the result of the bendingprocess, the first and second multi-tabs 161 and 162 are bent so as tobe symmetrical with each other. Therefore, it is possible to preventelectrical short circuits between the first and second multi-tabs 161and 162, and the case, the cap plate and/or the first and secondelectrode assemblies, which have polarities opposite to the first andsecond multi-tabs 161 and 162 from occurring during or after themanufacture of the secondary battery 100.

Referring to FIG. 9, a perspective view illustrating an example of abattery module using a secondary battery 100 having a structure forsuppressing multi-tab short circuits according to an embodiment of thepresent invention is illustrated.

As shown in FIG. 9, multiple secondary batteries 100 are arranged in aline and multiple bus bars 510 are coupled to the multiple secondarybatteries 100, thereby completing the battery module 1000. For example,a first electrode terminal 140 of one of the multiple secondarybatteries 100 and a second electrode terminal 150 of another adjacentsecondary battery 100 may be welded to each other using the bus bar 510,thereby providing the battery module 1000 including the multiplesecondary batteries 100 connected to one another in series. The bus bar510 may be made of aluminum or an aluminum alloy, and a first terminalplate 131 of the first electrode terminal 140 and a second terminalplate 141 of the second electrode terminal 150 may also be made ofaluminum or an aluminum alloy, thereby allowing the bus bar 510 to beeasily welded to the first electrode terminal 140 and the secondelectrode terminal 150.

Although the foregoing embodiments have been described to practice thesecondary battery having a structure for suppressing multi-tab shortcircuits of the present invention, these embodiments are set forth forillustrative purposes and do not serve to limit the invention. Thoseskilled in the art will readily appreciate that many modifications andvariations can be made, without departing from the spirit and scope ofthe invention as defined in the appended claims, and such modificationsand variations are encompassed within the scope and spirit of thepresent invention.

1. A secondary battery comprising: a case; an electrode assemblyaccommodated inside the case and having multi-tabs; and a cap plateclosing the case and having electrode terminals electrically connectedto the multi-tabs of the electrode assembly, wherein the surfaces of themulti-tabs are coated with insulating layers.
 2. The secondary batteryof claim 1, wherein the insulating layers include an insulating organicmaterial.
 3. The secondary battery of claim 1, wherein the insulatinglayers include an insulating inorganic material.
 4. The secondarybattery of claim 1, wherein the insulating layers include an inorganicfiller and an organic binder.
 5. The secondary battery of claim 1,wherein the electrode assembly comprises: a first electrode plateincluding a first current collector plate and a first electricallyactive material layer coated on the first current collector plate; aseparator positioned at one side of the first electrode plate; and asecond electrode plate including a second current collector platepositioned at one side of the separator and a second electrically activematerial layer coated on the second current collector plate, wherein themulti-tabs have a structure in which the first current collector plateis upwardly extended to an exterior side of the first electricallyactive material layer of the first electrode plate.
 6. The secondarybattery of claim 5, wherein the insulating layers and the separator arepositioned between the multi-tabs and the second electrode plate.
 7. Thesecondary battery of claim 5, further comprising a safety function layer(SFL) located on the second electrically active material layer, whereinthe insulating layers, the separator and the SFL are positioned betweenthe multi-tabs and the second electrode plate.
 8. The secondary batteryof claim 5, wherein the insulating layers are brought into contact withthe first electrically active material layer.
 9. The secondary batteryof claim 5, wherein the insulating layers are spaced apart from thefirst electrically active material layer.
 10. The secondary battery ofclaim 5, wherein the insulating layers are brought into contact with theseparator.